I went back and read the post, and I remembered it wrong. The effect is there for women with the same overall attractiveness rating, which is a stronger version than I originally posted.
> Another possibility is a more polarizing face makes some guys feel like they have a better chance.
This explains why guys would send messages, but not why they would rate pics highly. It’s a better fit for why guys would message girls with lower ratings, not girls with high ratings and high std. dev. The trick in their version is it’s not just “I think other guys aren’t into her”, it’s “I think other guys aren’t into her, but I am.”
But yeah, being a story that explains the data doesn’t make it true, and all sorts of stuff could be going on. And like the other poster pointed out their analysis is fun but not necessarily ironclad. For my part I figure there’s a ton of cultural signaling going on in dating pics that they can’t really account for.